<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>p9_固定定位</title>
    <style>
        .fu{
            background-color:darkgreen ;
        }
        .fu>div{
            width: 100px;
            height: 100px;
        }
        .z1{
            background-color: yellow;
        }
        .z2{
            background-color: red;
        }
        .z3{
            background-color: green;
        }
    </style>
</head>
<body>
      <div class="fu">
          <div class="z1">我是div1</div>
          <div class="z2">我是div2</div>
          <div class="z3">我是
          </div>
      </div>
</body>
</html>